The two heritage bodies have joined East Northamptonshire Council, which originally refused planning permission for the 127-metre high turbines close to Lyveden New Bield, to oppose the planned wind farm.

They fear the turbines will be visible from virtually everywhere on the property, affecting the appreciation of one of England's oldest garden landscapes, and the go-ahead for development could set a precedent for other heritage sites.

Last month the planning inspector backed an appeal by an energy company to let it install the turbines near the Grade I-listed heritage site, which is made up of an unfinished 17th century lodge and gardens, despite acknowledging it was "probably the finest surviving example of an Elizabethan garden".

He also accepted that Lyveden New Bield had a "cultural value of national, if not international significance".

But while he said the turbines would be a "distraction" which would harm the heritage site, he ruled the damage would not be substantial and was outweighed by the benefits of the scheme in meeting wider renewable energy targets.

The National Trust argued that the turbines would be prominent, modern and intrusive structures in a landscape which still evoked the site's historic Rockingham Forest surroundings.

The decision also undermined protection for heritage around the country, the trust warned.

The trust, English Heritage and the local authority said they had started legal proceedings under the Town and Country Planning Act 1990, in a bid to get the courts to examine the way in which the planning inspector made his decision.

The three organisations believe the inspector failed to properly assess the contribution the setting makes to the heritage value of the building and gardens.

The case will be heard at the Administrative Court in London within a few months.

Simon Thurley, chief executive of government body English Heritage, said: "We were extremely disappointed by the inspector's decision to allow the wind farm.

"Our challenge to his decision is not simply about the balance of professional judgment between heritage and renewable energy.

"The inspector did not adequately take into account the contribution that Lyveden New Bield's historic and rural surroundings make to its immense significance.

"In our view, therefore, he failed to have 'special regard' for the desirability of preserving the special interest of the listed building and its setting which the law requires of him as decision-maker in this case."

Dr Thurley described the planning inspector's decision as "highly unusual" and said it should not be allowed to become the benchmark for future wind energy developments.

Dame Fiona Reynolds, director general of the National Trust, said: "We fully support renewable energy and have made our own commitment to halve our dependence on fossil fuels by 2020.

"We have also backed a number of wind proposals where scale and setting have been considered appropriate.

"However, the decision to allow a development of this size so close to one of the country's most treasured historic places is both damaging to Lyveden New Bield and could have serious implications for other heritage sites across the UK."

East Northamptonshire Council leader Steven North said the council was committed to the use of renewable energy wherever it was practicable but "not to the detriment of the historic landscape".

"It is regrettable that it has come to this, but we fully support this legal challenge and will be working closely with the National Trust and English Heritage to protect this heritage site."

The Trust is currently fighting at least half a dozen plans to build turbines, including a massive offshore farm in the Bristol Channel and voiced concerns about the first turbines in the Lake District National Park.

Another recent battle is plans to build three turbines near Harwick Hall in Derbyshire.